1. Field of the Invention
The present invention relates generally to improved bag structures and particularly to high strength bags capable of retaining bulky, relatively heavy materials in sterile condition and whose strength is essentially unaffected even when subjected to steam sterilization.
2. History of the Prior Art
Various bags have been developed for retaining articles which are sterilized after being packaged. Such bags typically comprise a composite structure consisting of plastic sheet material and a membrane permeable to sterilizing vapors such as ethylene oxide or steam. For example, the above-referenced U.S. Pat. Nos. 3,472,369 and 3,761,013 disclose bags consisting generally of plastic sheet folded along longitudinal fold lines to define a longitudinal opening. The opening is covered by a readily removable, vapor-permeable closure membrane typically in the form of a paper strip. It has been found that when such bags are made large enough to hold bulky, relatively heavy materials, the stresses developed when the bag is filled may result in rupturing of the seals joining the plastic sheet material and paper membrane. This problem is aggravated when the filled bag is subjected to autoclaving, that is, steam sterilization, which by itself has the effect of weakening the paper membrane.
There is furthermore a present need for an autoclavable, flexible container or bag capable of retaining large amounts of hospital waste products which typically include a large percentage of liquid and semi-liquid masses. Such a need has arisen from the recent enactment of anti-pollution ordinances in certain areas which prohibit the incineration by hospitals of waste products, Such ordinances require waste products to be sterilized by autoclaving and then disposed of in the same manner as other refuse. Such waste products may include, besides the aforementioned liquid and semi-liquid surgical waste, disposable surgical instruments and apparel, bandages, sutures and petri dishes.
Currently, the aforementioned waste products are simply wrapped in paper or cloth and in this fashion subjected to the autoclaving process. Such improvised containers, however, often do not adequately retain their contents, particularly those in the liquid or semi-liquid state. Paper, especially, is prone to leakage and moreover, as stated, loses much of its strength when exposed to the autoclaving process.